HYPONATREMIA

Hyponatremia Is this TRUE hyponatremia? Check plasma osmolality Posm low → True Hyponatremia Posm normal or high → Pseudo-Hyponatremia Hyperglycemia Hypertriglyceridemia True Hyponatremia Is ADH appropriately suppressed? Check urine osmolality Urine osmolality <100 → ADH suppressed Polydipsia Decreased osmolar intake Abuse/neglect* Inappropriate formula Water intoxication Abuse/neglect* Inappropriate formula Iatrogenic ADH present Urine osmolality >100 Why is ADH present? Check clinical volume status Hypovolemic Renal (UNa >20, FeNa >1%) Osmotic diuresis (e.g., Diabetic Ketoacidosis*) Hypoaldosteronism Diuretics Polyuric Acute Tubular Necrosis Extra renal (UNa <10, FeNa <1%) GI losses (gastroenteritis, pyloric stenosis*) Insensible losses (Cystic Fibrosis, Burns*) Euvolemic SIADH Endocrinopathies Adrenal insufficiency Hypervolemic Low intravascular volume (↓ EABV) (Low UNa esp. <20): Congestive heart failure* Nephrotic syndrome* Nephritic syndrome* Sepsis* with capillary leak High intravascular volume (↑ EABV) (UNa >20, FeNa >1%): Renal Failure* *Indicates Key Condition This is not an exhaustive list of medical conditions.